<?php
/**
 * TDownload.php
 * from site    : www.jbuxe.com
 * 使用方法：
 * require_once 'download.class.php';
 * $filePath = './path/filename.html';
 * $downName = 'downName.html';
 * $down = new TDownload($filePath,$downName);
 * 或
 * $down = new TDownload();
 *
 * */

class TDownload
{
    public $filePath;
    public $downName;
    public $ErrInfo;
    public $is_attachment = false;
    public $_LANG = array(
            'err' => '错误',
            'args_empty' => '参数错误。',
            'file_not_exists' => '文件不存在！',
            'file_not_readable' => '文件不可读！',
        );
    public $MIMETypes = array(
            'ez' => 'application/andrew-inset',
            'hqx' => 'application/mac-binhex40',
            'cpt' => 'application/mac-compactpro',
            'doc' => 'application/msword',
            'bin' => 'application/octet-stream',
            'dms' => 'application/octet-stream',
            'lha' => 'application/octet-stream',
            'lzh' => 'application/octet-stream',
            'exe' => 'application/octet-stream',
            'class' => 'application/octet-stream',
            'so' => 'application/octet-stream',
            'dll' => 'application/octet-stream',
            'oda' => 'application/oda',
            'pdf' => 'application/pdf',
            'ai' => 'application/postscrīpt',
            'eps' => 'application/postscrīpt',
            'ps' => 'application/postscrīpt',
            'smi' => 'application/smil',
            'smil' => 'application/smil',
            'mif' => 'application/vnd.mif',
            'xls' => 'application/vnd.ms-excel',
            'ppt' => 'application/vnd.ms-powerpoint',
            'wbxml' => 'application/vnd.wap.wbxml',
            'wmlc' => 'application/vnd.wap.wmlc',
            'wmlsc' => 'application/vnd.wap.wmlscrīptc',
            'bcpio' => 'application/x-bcpio',
            'vcd' => 'application/x-cdlink',
            'pgn' => 'application/x-chess-pgn',
            'cpio' => 'application/x-cpio',
            'csh' => 'application/x-csh',
            'dcr' => 'application/x-director',
            'dir' => 'application/x-director',
            'dxr' => 'application/x-director',
            'dvi' => 'application/x-dvi',
            'spl' => 'application/x-futuresplash',
            'gtar' => 'application/x-gtar',
            'hdf' => 'application/x-hdf',
            'js' => 'application/x-javascrīpt',
            'skp' => 'application/x-koan',
            'skd' => 'application/x-koan',
            'skt' => 'application/x-koan',
            'skm' => 'application/x-koan',
            'latex' => 'application/x-latex',
            'nc' => 'application/x-netcdf',
            'cdf' => 'application/x-netcdf',
            'sh' => 'application/x-sh',
            'shar' => 'application/x-shar',
            'swf' => 'application/x-shockwave-flash',
            'sit' => 'application/x-stuffit',
            'sv4cpio' => 'application/x-sv4cpio',
            'sv4crc' => 'application/x-sv4crc',
            'tar' => 'application/x-tar',
            'tcl' => 'application/x-tcl',
            'tex' => 'application/x-tex',
            'texinfo' => 'application/x-texinfo',
            'texi' => 'application/x-texinfo',
            't' => 'application/x-troff',
            'tr' => 'application/x-troff',
            'roff' => 'application/x-troff',
            'man' => 'application/x-troff-man',
            'me' => 'application/x-troff-me',
            'ms' => 'application/x-troff-ms',
            'ustar' => 'application/x-ustar',
            'src' => 'application/x-wais-source',
            'xhtml' => 'application/xhtml+xml',
            'xht' => 'application/xhtml+xml',
            'zip' => 'application/zip',
            'au' => 'audio/basic',
            'snd' => 'audio/basic',
            'mid' => 'audio/midi',
            'midi' => 'audio/midi',
            'kar' => 'audio/midi',
            'mpga' => 'audio/mpeg',
            'mp2' => 'audio/mpeg',
            'mp3' => 'audio/mpeg',
            'wma' => 'audio/mpeg',
            'aif' => 'audio/x-aiff',
            'aiff' => 'audio/x-aiff',
            'aifc' => 'audio/x-aiff',
            'm3u' => 'audio/x-mpegurl',
            'ram' => 'audio/x-pn-realaudio',
            'rm' => 'audio/x-pn-realaudio',
            'rpm' => 'audio/x-pn-realaudio-plugin',
            'ra' => 'audio/x-realaudio',
            'wav' => 'audio/x-wav',
            'pdb' => 'chemical/x-pdb',
            'xyz' => 'chemical/x-xyz',
            'bmp' => 'image/bmp',
            'gif' => 'image/gif',
            'ief' => 'image/ief',
            'jpeg' => 'image/jpeg',
            'jpg' => 'image/jpeg',
            'jpe' => 'image/jpeg',
            'png' => 'image/png',
            'tiff' => 'image/tiff',
            'tif' => 'image/tiff',
            'djvu' => 'image/vnd.djvu',
            'djv' => 'image/vnd.djvu',
            'wbmp' => 'image/vnd.wap.wbmp',
            'ras' => 'image/x-cmu-raster',
            'pnm' => 'image/x-portable-anymap',
            'pbm' => 'image/x-portable-bitmap',
            'pgm' => 'image/x-portable-graymap',
            'ppm' => 'image/x-portable-pixmap',
            'rgb' => 'image/x-rgb',
            'xbm' => 'image/x-xbitmap',
            'xpm' => 'image/x-xpixmap',
            'xwd' => 'image/x-xwindowdump',
            'igs' => 'model/iges',
            'iges' => 'model/iges',
            'msh' => 'model/mesh',
            'mesh' => 'model/mesh',
            'silo' => 'model/mesh',
            'wrl' => 'model/vrml',
            'vrml' => 'model/vrml',
            'css' => 'text/css',
            'html' => 'text/html',
            'htm' => 'text/html',
            'asc' => 'text/plain',
            'txt' => 'text/plain',
            'rtx' => 'text/richtext',
            'rtf' => 'text/rtf',
            'sgml' => 'text/sgml',
            'sgm' => 'text/sgml',
            'tsv' => 'text/tab-separated-values',
            'wml' => 'text/vnd.wap.wml',
            'wmls' => 'text/vnd.wap.wmlscrīpt',
            'etx' => 'text/x-setext',
            'xsl' => 'text/xml',
            'xml' => 'text/xml',
            'mpeg' => 'video/mpeg',
            'mpg' => 'video/mpeg',
            'mpe' => 'video/mpeg',
            'qt' => 'video/quicktime',
            'mov' => 'video/quicktime',
            'mxu' => 'video/vnd.mpegurl',
            'avi' => 'video/x-msvideo',
            'movie' => 'video/x-sgi-movie',
            'wmv' => 'application/x-mplayer2',
            'ice' => 'x-conference/x-cooltalk',
        );

    public function __construct($filePath='',$downName='')
    {
        if ( !$filePath ) {
            $this->start($filePath,$downName);
        }

    }

    public function start($filePath='',$downName='')
    {
        if ($filePath == '' AND !$this->filePath)
        {
            $this->ErrInfo = $this->_LANG['err'] . ':' . $this->_LANG['args_empty'];
            return false;
        }

        if ($filePath == '') $filePath = $this->filePath;

        if (!file_exists($filePath))
        {
            $this->ErrInfo = $this->_LANG['err'] . ':' . $this->_LANG['file_not_exists'];
            return false;
        }

        if ($downName == '' AND !$this->downName) $downName = $filePath;
        if ($downName == '') $downName = $this->downName;
        // 文件扩展名
        $fileExt = substr(strrchr($filePath, '.'), 1);
        // 文件类型
        $fileType = $this->MIMETypes[$fileExt] ? $this->MIMETypes[$fileExt] : 'application/octet-stream';
        // 是否是图片
        $isImage = False;
        /*
        简述: getimagesize(), 详见手册
        说明: 判定某个文件是否为图片的有效手段, 常用在文件上传验证
        */
        $imgInfo = @getimagesize($filePath);
        if ($imgInfo[2] && $imgInfo['bits'])
        {
            $fileType = $imgInfo['mime'];       // 支持不标准扩展名
            $isImage = True;
        }
        // 显示方式
        if ($this->is_attachment)
        {
            $attachment = 'attachment';     // 指定弹出下载对话框
        }
        else
        {
            $attachment = $isImage ? 'inline' : 'attachment';
        }
        // 读取文件
        if (is_readable($filePath))
        {
            /*
            简述: ob_end_clean() 清空并关闭输出缓冲, 详见手册
            说明: 关闭输出缓冲, 使文件片段内容读取至内存后即被送出, 减少资源消耗
            */
            ob_end_clean();
            /*
            HTTP头信息: 指示客户机可以接收生存期不大于指定时间（秒）的响应
            */
            header('Cache-control: max-age=31536000');
            /*
            HTTP头信息: 缓存文件过期时间(格林威治标准时)
            */
            header('Expires: ' . gmdate('D, d M Y H:i:s', time()+31536000) . ' GMT');
            /*
            HTTP头信息: 文件在服务期端最后被修改的时间
            Cache-control,Expires,Last-Modified 都是控制浏览器缓存的头信息
            在一些访问量巨大的门户, 合理的设置缓存能够避免过多的服务器请求, 一定程度下缓解服务器的压力
            */
            header('Last-Modified: ' . gmdate('D, d M Y H:i:s' , filemtime($filePath) . ' GMT'));
            /*
            HTTP头信息: 文档的编码(Encode)方法, 因为附件请求的文件多样化, 改变编码方式有可能损坏文件, 故为none
            */
            header('Content-Encoding: none');
            /*
            HTTP头信息: 告诉浏览器当前请求的文件类型.
            1.始终指定为application/octet-stream, 就代表文件是二进制流, 始终提示下载.
            2.指定对应的类型, 如请求的是mp3文件, 对应的MIME类型是audio/mpeg, IE就会自动启动Windows Media Player进行播放.
            */
            header('Content-type: ' . $fileType);
            /*
            HTTP头信息: 如果为attachment, 则告诉浏览器, 在访问时弹出”文件下载”对话框, 并指定保存时文件的默认名称(可以与服务器的文件名不同)
            如果要让浏览器直接显示内容, 则要指定为inline, 如图片, 文本
            */
            header('Content-Disposition: ' . $attachment . '; filename=' . $downName);
            /*
            HTTP头信息: 告诉浏览器文件长度
            (IE下载文件的时候不是有文件大小信息么?)
            */
            header('Content-Length: ' . filesize($filePath));
            // 打开文件(二进制只读模式)
            $fp = fopen($filePath, 'rb');
            // 输出文件
            fpassthru($fp);
            // 关闭文件
            fclose($fp);
            return true;
        }
        else
        {
            $this->ErrInfo = $this->_LANG['err'] . ':' . $this->_LANG['file_not_readable'];
            return false;
        }
    }
}
